diff --git a/src/flake8/plugins/pyflakes.py b/src/flake8/plugins/pyflakes.py
index e2ef2c3..880373a 100644
--- a/src/flake8/plugins/pyflakes.py
+++ b/src/flake8/plugins/pyflakes.py
@@ -97,7 +97,7 @@ class FlakesChecker(pyflakes.checker.Checker):
                     with_doctest = True
 
         super(FlakesChecker, self).__init__(
-            tree, filename, withDoctest=with_doctest
+            tree, filename=filename, withDoctest=with_doctest
         )
 
     @classmethod